1. Technical Field of the Invention
The present invention relates to networks, and more specifically, to a system and method of symbolic addressing and translation in telephone, cellular, data communication, or other networks.
2. Description of the Related Art
A network is a collection of points (called origin points, transit points or destination points collectively called nodes) and links between these points. The network transfers items of material substance or information, which are collectively referred to as traffic, from origin points (OP) through the links to a node where the item being transferred is routed to another link for transport to a destination point (DP).
An origin point is where an item enters a network. A destination point is the final place where an item is to be delivered within the network. In most networks, each origin point can also function as destination point, and likewise, each destination point can also function as an origin point. Usually a points status depends only on the use of the point. Commonly identifiable points include telephones, cellular phones, data terminals and physical street addresses. Links are paths of travel. Commonly identifiable links include wires, radio waves, guided and/or unguided electromagnetic waves, laser beams, roads, pipelines, corridors, vehicle delivery routes, or other transmission paths, and may include antennas or other devices to facilitate the reception or transmission of traffic. Network node transit points are located at link intersections. Transit points accept incoming items (for example data or voice signals in a telephone network), and based on routing information which is logically associated with the item, the transit point routes the items to a link which will then carry the item to another transit point or to a predetermined destination point. Transit points may include telephone switching equipment, an Internet server, airports, rail track switches, depots, and the like.
The routing information which is logically associated with an item at a node commonly uses a symbolic address (SA), otherwise known as a symbolic network address. The SA may be logically associated with a physical item, a separate channel, or a logically different network such as exchanging telephone numbers in Internet databases. An SA may designate the point of origin of an item and/or the destination point of an item. Examples of distinct explicit SAs include "telephone" directory numbers (DNs) and residential or business street addresses. Multiple devices may be used to complete the transmission of an item. For example, the telephone line designated by a particular telephone number may terminate to a telephone, cellular phone, fax machine, or computer. In the prior art, there has been no practical network method to indicate or control the functional properties or protocol of a terminal point, and to thereby preferably route traffic between compatible origin and destination points. For example, a user of a voice telephone cannot usefully communicate with a telefax machine.
At a transit point, switching algorithms are utilized to direct the flow of traffic from an origin point to a destination point using an item's SA. The most common algorithm uses tables, called translation tables (also called lists, arrays, or data bases), which comprise predetermined lists of matched inputs (typically destination point SAs) with corresponding possible outputs such as specific links. Various tables may be selected based on factors such as date, time of day, weather, or any variety of conditions. Ideally, the transit point will use the destination SA to select an optimal path of travel for an arriving item. The methods of determining the method of item travel are dependent upon the use of a distinct explicit SA for each physical point in the network.
Prior Art Example 1, A Mail or Parcel Delivery System
A mail or parcel system is a simple network. Each resident has a resident address and each business has a corresponding business address, where an address serves as an origin point (the return address) or destination point (the location the item is addressed to). The links are the roads and other transportation routes that make the delivery of the mailed items possible. The post offices and parcel handling offices serve as transit point nodes--sorting mail or parcels and directing it to appropriate links for delivery to designated DPs.
In a typical mail network operation, a user addresses an item with an explicit address indicating where the item is to be sent (a symbolic DP) and the user's own return address (a symbolic OP), then places the item in a mailbox or parcel drop box (a physical OP) and effectively consigns the item to the transportation network. The postal or parcel service will then carry the item by road, rail, air or water (all of which are links) to a post office or parcel handling office transit points. At such an office, the symbolic DP is read. Provided the DP is legible and meets certain criteria of the network, the office sorts the item according to the link or series of links which optimize the delivery of the item. Further sorting may occur at other network nodes as well. The item is then transported across the selected links and is delivered to the DP of the addressee.
Passenger and freight transportation networks such as airlines, bus lines, rail and water vessel lines also operate in a similar manner, and internal networks such as luggage handling networks of conveyor belts in airports, item picking operations for packing an order in a warehouse, or pneumatic tube conveyors used in offices are further examples of a transportation network which uses symbolic DP addressing. In some cases, the DP (and OP) information is associated with the item in transportation networks by means of a label or other media such as bar coding, magnetic stripe coding, attached/embedded radio transponder, or other means which can be read or sensed by human workers or appropriate equipment directly from the item itself. In other cases, a logically separate or even physically separate data communication network is established to convey the DP (and OP) information associated with each item, for control of the sorting and switching.
Prior Art Example 2, A Data Communication Network
The Internet and associated electronic mail (e-mail) networks are examples of a data communication network. The originator of an e-mail message can type a message, and can also attach data files of various types to said message, and then can consign said message with its attachments to the e-mail network together with a header which comprises the DP SA (for example: john.smith@bigcompany.com), and also the OP SA. Internet users may also establish a network route to a so-called hyper-text telecommunications protocol server by use of a DP SA of the form http://www.interestingstutf.com. In an Internet network, items consisting of packets of digital data travel through links to nodes, where they are sorted based on the DP SA, and then sent on their way via an outgoing link selected to optimize the delivery of the item. In a two-way communication, other items or packets of data traffic go from the so-called destination point to the so-called origination point. In many networks such as broadcasting systems, cable television distribution, electric power distribution networks, water and gas distribution pipeline systems, Internet http operations, and the like, most or all of the traffic flows from the so-called destination point to the so-called origin point.
Many networks including these also have the structural property that some nodes are used for both transit and also for origination and destination. Many networks having a so-called "multi-drop" topology such as local area networks (LANs) for data communication, and the aforementioned gas, water, and electric networks have this topological structure. Internet networks may utilize some links from other networks, such as the public switched telephone network (PSTN), to form part or all of their physical link structure, although the points and nodes are generally made up of distinct equipment from said other networks such as the PSTN.
Prior Art Example 3, A Telephone Network
A PSTN (or a non-public telephone network as well) provides another example of a prior art network. A PSTN is comprised of telephones, fax machines, computers, cellular telephones and other devices which have assigned SAs which can be used as origination points or destination points. In a PSTN, each SA (telephone number) corresponds to a single link dedicated to that SA called a "subscriber line" (SL). PSTNs use wire lines or electromagnetic waves as links, and possess switching equipment at a central offices (CO) or various transit switching offices. In a telephone network, the switching equipment is the network node.
The PSTN industry has voluntarily agreed to use the standard control message protocol called common channel signaling system number 7, (S7). To simplify the discussion, and because S7 is well known and widely used in the PSTN art, S7 specifics are discussed only where necessary. The present invention is not limited to S7-related embodiments.
Each subscriber line or channel in a switch is assigned an internal line appearance number (ILAN) by the appropriate telephone switching administration. The ILAN is used in the internal call processing of a switch to identify a line for purposes of wiring repairs, to identify which line is originating a call, to route a connection within the switch to a particular destination, and the like. In effect, the internal ILAN numbering system of a switch can uniquely relate the internal number assigned for each subscriber line in use to the physical rack, shelf, and printed wiring card where the line appears.
In a cellular or personal communication system (PCS) system, other internal data elements, often proprietary, play the same role as the ILAN does in a wired telephone switch. However, due to handoffs, the ILAN-equivalent in a cellular or PCS system changes from time to time as the telephone involved in a conversation moves from cell to cell and is consequently in radio communication with different base radio channels in different cells. Due to their design, a cellular or PCS switch can maintain a connection despite the timely changes in ILAN, and the changes in internal ILAN in such a situation do not prevent the operation of the present invention.
Telephone directory numbers (DNs) are not the same as ILANs in a modern electronic telephone switch. DNs and ILANs are related to each other by means of translation tables. Then, as subscriber lines are disconnected and new subscriber lines are added to a PSTN, the telephone switching administrator needs only to assign the new subscriber line to an existing ILAN through software programming which modifies the data in said translation tables, rather than requiring a hardware or wiring change.
When the person originating a telephone call lifts a telephone handset A and dials digits, the central office switching equipment receives an internal signal which is identified with the ILAN of the OP line A. When an incoming call comes from a different OP B toward this DP A, its DP is identified as the DN of line A. When the DN is thus given, the translation table used is organized to translate DN into ILAN, so the proper destination line can be connected for such an incoming call When the ILAN is given, as in the case of the origination from line A, a distinct translation table organized to translate ILAN into DN is used, so the proper DN can be used for calling line ID services and so the call will be billed to the proper origination line. Links between telephone switches are called trunks. In most installations, a telephone switch has a plurality of trunks, each trunk or group of trunks leading to a different transit or destination switch in the PSTN. Other translation tables use proprietary internal numbering identifications to select the optimum outgoing trunks to reach a specific ultimate DP, based on translation tables which relate the SA (or a portion thereof) of that particular DP to the optimum trunk.
Various transit switches in the PSTN likewise use appropriate translation tables to select the optimum outgoing trunk to convey the item to its ultimate destination. The result of using such translation tables is responsive to the DN of the DP, or to some pre-designated portion of the DN, such as the area code or the central office code. When a called telephone has answered an incoming call, a two-way connection is established through the PSTN trunks and transit switches. In older telephone technology such a connection was established by electrically connecting appropriate wires for each conversation, and the information content of the conversation was conveyed in the form of analog voltage waveforms which were representative of the analog audio frequency waveform occurring at the OP and DP equipment. In modern telephone technology, digitally coded representations of audio wave forms are used and the connection is established by transmitting digital traffic in blocks of various quantities of bits (such as 8 bits, 384 bits, 424 bits, or other) through the links, which permit the transmission of multiple channels via the same link.
FIG. 1 (Prior Art) illustrates the relevant features of a PSTN. The PSTN is comprised of: a first central office switch 100, a second central office switch 200, a first a first telephone handset 102 assigned to SL 19722345678, a second telephone handset 104 assigned SL 19722348114, a third telephone handset 106 assigned SL 1972234987, a fourth telephone handset 202 assigned SL 12147654321, a fifth telephone handset 204 assigned SL 12147652784, a sixth telephone handset 206 assigned SL 12147659156, a transit trunk switch 300 and a signal transfer point (STP) 400. Various telephone lines 101 connect telephone handsets 102, 104, 106, 202, 204, 206 with the COs 100, 200.
The first CO is assigned area code 972, and central office code 234, and contains within it an internal controller computer 110, a first line module 132, a second line module 134, a third line module 136 and a switching matrix 140. The internal control computer 110 contains a central processing unit (CPU) 112 and data memory 114. Data memory 114 stores tables 115-118.
The second CO is assigned area code 214, and central office code 765, and contains within it an internal controller computer 210, a fourth line module 232, a fifth line module 234, a sixth line module 236 and a switching matrix 240. The internal control computer 210 contains a central processing unit (CPU) 212 and data memory 214. Data memory 214 stores tables 215-218.
In operation, a user lifts the first telephone handset 102 and the first line module 132 detects that its assigned point has been activated. The user then hears a dial tone, and dials the directory number (DN) of the fourth telephone handset 202. The first line module 132 communicates with the DN of the telephone handset 202 with the first internal control computer 110 through internal data links 138.
Table 1 is a simplified partial CO table which shows ILANs, the status of those ILANs, and the last four digits of the DN assigned to an individual ILAN. A table such as Table 1 is typically used for billing purposes and to allow the use of calling line identification (CLID) functions.
TABLE 1 ______________________________________ Line Appearance Number In/Out of Service Last 4 Digits of DN ______________________________________ 19316 1 8114 19317 5678 19318 4987 19319 -- ______________________________________
On a computing level, the CPU 112 uses Table 1 to translate the ILAN of the line module 132 into the DN of its assigned SL. Here, Table 1 is used to find that first line module 132, associated with ILAN 19317, is in service (represented in Table 1 by a "1", whereas a "0" would indicate that a line is out of service) and that the first line module 132 is assigned to DN 5678. Although a four digit partial DN is shown, it should be understood that the use of larger partial DNs can be used and their use is well known in the art.
The control computer 110 proceeds to separate the dialed digits into code sections. For example, the dialed digits 1-214-765-4321 have a country code section "1," an area code section "214," and a central office (CO) code section "765."
Table 2 shows which trunk group is assigned to an area code. In our example, area code 214 leads to a trunk group 143 which is identified with proprietary internal outlet trunk group number 3 in Table 2. Proprietary group 3 is identified with outgoing trunk 143.
TABLE 2 ______________________________________ Area Code Outlet Trunk Group Number ______________________________________ 213 1 214 3 215 2 216 2 ______________________________________
Thus, the control computer 110 detects that the dialed DN is a United States non-local call by detecting the leading "1", that the call is destined for area code "214", and for the central office number "765" within area code "214." For illustrative purposes, should the call have been directed to a DN within the same CO 100, outgoing trunks would not be selected, but a table such as Table 3 would have been used to complete the transaction to the proper ILAN and DP. Table 3 represents data resident in data switch 200, but a similar table is resident in switch 100 and other switches. Table 3 translates the CO's DNs into ILANs.
TABLE 3 ______________________________________ Last 4 Digits of In/Out of Line Appearance DN Numberce ______________________________________ 4319 0 -- 4320 31597 4321 26433 4322 1325 ______________________________________
After the control computer 110 selects the appropriate trunk group 143, the control computer 110 selects an idle line or channel within the trunk group 143 which is then connected to the originating telephone handset 102 through an internal switching matrix 140.
The control computer 110 then sends an initial address message (IAM) signal on the signaling channel 401 to inform the signal transfer point (STP) 400 of the line being used within trunk group 143 to send the transmission. The STP 400 uses this information to inform the transit trunk switch 300 and the second CO 200 of the impending transmission. The transit trunk switch 300 may possess computers, tables, and a switching matrix similar to those shown in the COs 100, 200. The transit trunk switch 300 routes the transmission, in a manner similar to that already described, from the first CO 100 to the second CO 200 on the outgoing link 303. Next, processor 210 examines the dialed digits data within the IAM. The last four digits of the DN are then used as the input to Table 3. From Table 3, it is seen that DN 4321 is in service and corresponds to line appearance number 26,433 which runs to line module 232. Control computer 210 then tests to see if the line is idle or busy via means well known in the art, and rings the line if not busy.
The control computer 210 then sends a S7 formatted message back to the control computer 110 through the signalling link 404 via STP 400 to confirm the ringing status of the incoming transmission. The control computer 210 also signals a tone generator (not shown) to send a ringing tone to the originating DN. Once the destination DN telephone handset 202 is lifted, the control computer 210 connects the transmission from the transmission trunk switch 300, through the switching matrix 240, and to the appropriate line module 232 and signals this status change back to original switch 100. As soon as either party hangs up the telephone handsets 102, 202 the CO for that telephone handset detects the event electronically and sends a release signal to the other CO and releases the relevant network links. The other CO typically responds to the release signal to confirm release of the transmission.
Table 4 illustrates that trunk groups are also assigned to central switching offices in a similar manner. For example, within an area code 214, end office code 767 leads to Outlet Trunk Group Number 1 from transit switch 300.
TABLE 4 ______________________________________ End Office Code Outlet Trunk Group Number ______________________________________ 764 2 765 3 766 3 767 1 ______________________________________
Problems in the Prior Art
Most users of both a voice telephone and a fax machine are forced to obtain a separate distinct SA for each device to allow proper transmission. This is an example of the causes which have resulted in number exhaustion and the need for many new area codes which costs telephone administrators and telephone subscribers money and resources to modify the system and change all identification (directories, stationery and the like). Furthermore, with enough available DNs in a network, systems already exist that allow for error detection of incorrectly entered DNs. The exhaustion of available DNs reduces or eliminates the ability to assign DNs in such a way as to allow such error detection. Numerous other improvements in telephone dialing plans are desirable, but are not possible to implement in the prior art, due to the pressure of number exhaustion.
In the prior art, a telephone line user is normally forced to obtain a separate distinct SA for each line and/or device connected to the PSTN. This has resulted in number exhaustion and the need for many new area codes which is inconvenient and costs telephone subscribers and administrators money, and which causes delayed or often misdirected communication.
Parity check codes or alternating digit check sum codes are just two of many error protection codes well known in the art, and are used in internal portions of existing telecommunications networks, where data is exchanged from one machine to another. Error protection codes for human entry of such numbers as credit card and bank account numbers have already been used in data processing systems. But error protection codes have not been used heretofore for the human entry of a DN or other symbolic network address in a telecommunications or transportation network. The exhaustion of available DNs reduces or removes the ability to allow DN entry error protection or to use protected central office codes (a method well known in the art to allow use of local telephone 7 digit dialing in boundary areas of different area codes).
The use of multiple DNs by a user can create other problems. For example, the user must often list four or five telephone numbers on business cards, directories and stationery for voice, fax, cell phone, children's residential line(s), etc. Multiple DNs also confuse persons trying to reach the user, resulting in faxes going to voice lines and voice calls terminating at data receivers.
So-called "500" or "personal agent" number services exist in the prior art. In these services, callers dial one special DN such as 1 500 876 5432 to reach a particular person. As a result of calling this one DN, pre-programmed switching equipment will in turn dial to one or more pre-designated explicit DNs, either sequentially (in what is called a hunt sequence) or simultaneously, and then connect the originator to the first one which answers. This personal agent service in the prior art is ultimately unsatisfactory for many users because: first, it requires the use of one additional explicit DN rather than reducing the quantity of explicit DNs; second, it does not distinguish various distinct functional properties such as a voice line compared to a fax line and would require use of a separate and additional personal agent explicit DN for each distinct line group having a distinct functional property set; third, due to these two aspects of its operation, it exacerbates rather than alleviates the basic problem of number exhaustion.
Some networks, or portions of certain networks, are distinguished from others, which are technologically similar and nominally compatible, because they are operated by unaffiliated or competitive businesses. In some cases, these distinguishable networks do not serve all destinations for legal or business competitive reasons, even though an otherwise valid SA is used by the originator. In telecommunications networks, the advent of local number portability (LNP), now mandated by the government telecommunications regulatory agencies of several nations to encourage local exchange carrier competition, requires the telephone network as a whole to establish a network path to the proper destination for a user, even when that user's telephone line is now on a "new" competitive local exchange operator/administrator's CO switch, and is no longer served by the CO having the nominal area code and CO code of that user's pre-existing explicit DN. Various methods for effectively either forwarding such calls or re-originating such calls after performing a global title translation (telephone jargon for substitution of a distinct destination explicit DN derived from an appropriate translation data list) on the dialed digits have been espoused by various interests in the telephone industry. All of these proposed methods have the undesirable result of requiring multiple explicit DNs for each such subscriber, and thus greatly exacerbating the number exhaustion problem. Similarly, in transportation networks, certain SAs are not accessible to all networks, such as the post office box number which is not accessible to a non-postal parcel delivery service. In the propr art of transportation there is no network solution to this problem and such items are usually undeliverable.
Therefore, there exists the need for a system and method of network addressing and translation which is substantially automatic is more accurate than the state of the art, and can automatically connect an origin point to a corresponding compatible destination point.